U.S. Pat. No. 5,126,159 (BUEHLER AG) describes a process for the manufacture of pasta where the three operations of mixing, kneading and extrusion are performed continuously in three separate devices, connected in series, belonging to the same plant. Measured quantities of the semolina and the water are provided directly therein, in a rapid paddle mixer which delivers a mixture in the form of lumps of moistened semolina. These lumps are introduced into a kneading device consisting of two screws rotating in the same direction and meshing with each other, where they are processed into a dough of dry and brittle appearance. This dough is introduced into a single-screw extruder where it is pressed through a die under the pressure exerted by the screw, in the form of pasta of section defined by the shape of the die openings.
U.S. Pat. No. 5,186,539 (BUEHLER AG) describes a process for the manufacture of pasta where the two operations of mixing and kneading are carried out in the same device, consisting of two screws rotating in the same direction and meshing with each other, and where the extrusion operation is carried out in a separate device, namely a single-screw extruder fed by the first device.
U.S. Pat. No. 5,139,806 (NESTEC S.A.) describes a process for the manufacture of pasta where the three operations of mixing, kneading and extrusion are carried out continuously in a single device with two screws rotating in the same direction and meshing with each other, the pressure required for pressing the dough through the die being exerted by the device with two screws itself.
Each of the three processes described above represents a significant step towards the simplification and the carrying out, in an increasingly shorter time, of the manufacture of pasta. However, the last of these processes, apparently the simplest and most rapid, subjects the said device with two screws to very high stresses since it has to withstand alone all the strain and develop alone all the energy required for the mixing, kneading and extrusion operations, without counting the fact that it subjects the dough to high shearing.
The aim of the present invention is to propose a process for the manufacture of pasta and equipment for its implementation which are simple, consume relatively little energy and subject the said mixture of cereal flour or semolina and water to only a relatively low shearing.